The Problem Gambling Severity Index (PGSI) was the reference standard. Measurements: The brief screening instruments were the Lie/Bet Questionnaire, Brief Problem Gambling Screen (BPGS) (two- to five-item versions), NODS-CLiP, NODS-CLiP2, Brief Biosocial Gambling Screen (BBGS) and NODS-PERC. Participants: A total of 837 patients were recruited consecutively between June 2015 and January 2016. Setting: Eight mental health services in Victoria, Australia. Design: The classification accuracy of nine brief screening instruments was compared with multiple cut-off scores on a reference standard. The primary aim was to compare the classification accuracy of nine brief problem gambling screening instruments (two to five items) with a reference standard among patients accessing mental health services.

Background and aims: Despite the over-representation of people with gambling problems in mental health populations, there is limited information available to guide the selection of brief screening instruments within mental health services.

Lie bet gambling screen